git clone fails - always requires authorization which fails

The command
`git clone --depth=1 https://github.com/github/copilot.vim.git ~/.config/nvim/pack/github/start/copilot.vim`

as given in README.md always asks for authentication.

Neither my alias name nor my email address (with password) is being accepted. The password query always shows the entered account suffixed with "@github.com".

The same credentials are valid for authenticate at github.com.
The destination directory is existing.

Platform: Linux Mint 22.3
neovim as delivered with Linux Mint 22.3 (v0.9.5)
git as delivered with Linux Mint 22.3 (2.43.0)

Any ideas ?

Start by reproducing the `git clone` command shown in README.md on the listed Linux Mint, Neovim, and Git versions. Then inspect the README setup instructions and verify whether the documented repository access method works without rejected authentication; done means the setup command succeeds or the documentation accurately explains the required access.

索引モデルが issue の本文から書いたものです。